Identification and quantification of volatile organic compounds emitted by organic fertilizers: Investigating the effect of temperature

Le résumé fourni par la source

The environmental implications of volatile organic compound (VOC) emissions from organic fertilizers, such as green waste compost (GWC), sewage sludge (SS), and digestate of cattle manure have gained significant attention but their contributions to air pollution, including ozone formation, remain unclear. This study explores the VOC emission profiles of these fertilizers under controlled temperature conditions (10 °C, 20 °C, and 30 °C) using Proton Transfer Reaction-Time-of-Flight Mass Spectrometry (PTR-ToF-MS). VOC emissions were found to be highly diverse with a total of 413 VOCs identified, with GWC emitting the highest number of compounds and digestate the least. Oxygenated VOCs predominated in all samples, comprising up to 83% of the total VOC flux in certain cases. Most of emission rates exhibited strong temperature dependence, with higher temperatures amplifying the release of O-VOCs, hydrocarbons and nitrogen containing VOCs. While GWC emissions are the most affected by temperature, the effect differs for each VOC, with some VOCs even decreasing when temperature increases. GWC demonstrated the highest ozone formation potential (OFP), followed by SS and digestate, highlighting its significant role in photochemical smog formation. The OFP is mainly explained by emissions of highly reactive hydrocarbons. These findings underscore the importance of managing organic fertilizers to mitigate their environmental impact and contribute to sustainable agricultural practices. • Compost is the highest VOC emitter, followed by SS and digestate. • OVOCs and HC are the most emitted chemical families, and SS emits more S-VOCs. • Temperature increases most of VOC emissions, and is more pronounced for compost. • Ozone Forming Potential is higher in compost, and HC main contributors. • Digestate has a lower impact on air quality.

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